The present invention relates to a semiconductor apparatus and a method for manufacturing the same, and more particularly, to a wafer cassette for use in semiconductor manufacture and management, a method for manufacturing the cassette, and equipment for semiconductor fabrication.
Currently, the automated manufacture of a semiconductor device includes three phases: a designation phase where process programs for equipment to manufacture the semiconductor device are designated by an automated system, a loading phase where a wafer cassette is loaded onto equipment by an operator or an auto-guided vehicle (AGV), and a process-performing phase. Here, in order to prevent errors in the process operation by the improper loading of the cassette onto the equipment by the operator or the AGV, a fixed bar code reader is situated on the equipment to read a bar code affixed to the cassette.
FIGS. 1A and lB are front and side views, respectively, of a conventional cassette for semiconductor fabrication and management. Reference numeral 10 denotes a cassette and reference numeral 15 denotes a bar code.
The cassette 10, as a container for wafers, is generally used for carrying 25 wafers at a time, and the bar code 15 is used for the specific identification of the cassette 10. The bar code 15 is located on the sidewalls as well as the front wall of the cassette 10. The bar code 15 is affixed to the center of the sidewalls of the cassette 10, in parallel with the walls of the cassette 10.
FIGS. 2A and 2B illustrate a loader/unloader portion of conventional equipment for semiconductor fabrication having a cassette identifying apparatus for reading the bar codes on the front walls and side walls of the cassette 10, respectively. Here, in addition to the reference numerals used in connection with FIGS. 1A and 1B, reference numeral 20 denotes an loader/unloader portion of the equipment for semiconductor fabrication, reference numeral 30 denotes a bar code reader, reference numeral 40 denotes a beam window, and reference numeral 45 denotes a beam.
FIG. 2A is a side view of the loader/unloader portion 20 for loading/unloading a cassette, showing how to read the front bar code. The bar code reader 30, i.e., a cassette identifying apparatus, is provided in the frontal part of the loader/unloader 20 (where an operator would be positioned).
FIG. 2B is a front view of the loader/unloader 20, showing how to read the side bar code. The bar code reader 30 is installed between cassettes loaded on the loader/unloader portion 20.
When an operator or AGV loads the cassette 10 containing wafers onto the loader/unloader portion 20, the bar code reader 30 reads the bar code of the cassette 10 to ensure the proper sequence of manufacturing steps are carried out. The manufacturing process only proceeds after determining whether the identified bar code of a cassette is correct. The cassette 10 whose bar code 15 is verified by the bar code reader 30 is moved from the loader/unloader portion 20 for subsequent processing.
When the cassette 10 is loaded to place wafers contained therein perpendicularly to the upper plane of the loader/unloader portion 20, i.e., when the base plane of the cassette 10 is in contact with the upper plane of the loader/unloader portion 20, the bar code reader 30 reads the bar code inscribed on the front wall or sidewalls of the cassette 10.
On the other hand, if cassette 10 is loaded to place wafers contained therein in parallel with the upper plane of the loader/unloader portion 20, i.e., when the rear plane of the cassette 10 is in contact with the upper plane of the loader/unloader portion 20, the bar code reader 30 reads only the bar code inscribed on the sidewalls of the cassette 10. The bar code on the front wall of the cassette 10 is not read.
According to the above conventional wafer cassette and equipment for semiconductor fabrication having a cassette identifying apparatus, a change in the step sequence of a semiconductor manufacturing process is prevented by identifying the cassettes using a bar code reader. Certain disadvantages, however, are present.
First, when the bar code reader 30 is positioned in the frontal part of loader/unloader portion 20 (see FIG. 2A), it is difficult for an operator or AGV to load the cassette 10 onto the loader/unloader portion 20 since the bar code reader 30 is installed on the loader/unloader portion 20. In this conventional configuration, therefore, when loading/unloading a cassette 10, the operator or AGV must lift the cassette 10 up and over the bar code reader 30.
Second, during such a loader/unloader operation, there is a significant likelihood for the wafers to become damaged by cracking. That is, when the operator or AGV performs the loading/unloading operation, there is the potential for the cassette 10 and the bar code reader 30 to collide with each other.
Third, the number of cassettes to be loaded on the loader/unloader portion 20 is limited by the bar code reader 30, thus lowering productivity. That is, since a certain amount of space must be provided to house the bar code reader 30 and the beam 45 generated therefrom, the number of the cassettes which can be loaded on the loader/unloader portion 20 is restricted, which in turn reduces the total number of wafers which can be prepared per unit process.